Compared with the straight-line line balancing problem, the problem with U-line is more complicated because tasks can be grouped by moving forward, backward, or simultaneously in both directions, through the precedence network.
In this thesis, the U-line line balancing problem is studied in two cases depending on whether the moving time of operator is considered(CASE II) or not(CASE I). The moving time occurs when he moves from one machine to another to carry out the assigned tasks at his workstation during a given cycle time.
For each case, the problem is formulated into the mathematical programming model. Due to its problem complexity, we develop two heuristic algorithms based on the simulated annealing search method and the PATH search method. To show the validity of the proposed algorithms, example problems are solved. The results are compared with an existing algorithm for the CASE I. For the CASE II problem, we suggest a lower bound of an optimal solution.
